Research and development in microelectronics have continued to produce astounding progress in MEMS technology. MEMS technologies are becoming ever more prevalent in society every day. Use of MEMS technology has limitless applications through modular measurement devices such as accelerometers, gyroscopes, actuators, microphones, and sensors including pressure sensors and inertial sensors.
Likewise, applications for miniature sensors are wide ranging and include embedded sensors. One area of interest involves providing required electrical power to embedded sensors. Conventional power supplies, such as batteries, can be disposed external to sensors. Batteries are not generally a viable solution for devices such as embedded sensors. Batteries contain a finite amount of energy and have a limited lifetime. Batteries also can contain hazardous chemicals, can be quite bulky and can fail without notice.
For those applications in which sensors are completely embedded in a structure with no physical connection to a location outside the structure or in which sensors are embedded in moving locations, supplying power is generally difficult. As a result, these sensors typically need their own self-powered power supply.
Further, some applications utilize a large network of sensors, such those with thousands of sensors. It is impracticable to manage and replace batteries for such a large number of sensors. Therefore, a self-powered power supply would allow for expanded use of large networks of sensors by alleviating battery maintenance concerns.
Accordingly, it is desirable to provide MEMS devices for harvesting sound energy and methods for fabricating such MEMS devices. Further, it is desirable to provide a monolithic MEMS device including a suspended structure and proof mass that are adjusted to have a resonant frequency that matches the frequency of sound at a selected location of use. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.